Health Consultation
Exposure Investigation of Private
Drinking Water Wells
New River, Maricopa County, Arizona

Prepared by
Arizona Department of Health Services
Office of Environmental Health
Environmental Health Consultation Services
Under Cooperative Agreement with the Agency for Toxic Substances and Disease Registry (ATSDR)

Background
New River, Arizona is a rapidly growing but still predominately rural community in northern
Maricopa County—approximately 20 miles north of Phoenix, Arizona. The 2000 census
estimated a population of 10,740. Residents rely exclusively on private domestic wells for
potable water. Some residents share wells between households. All residents’ well water contains
some arsenic, which occurs naturally in rock formations in New River area as well as the Agua
Fria Basin and the Verde River Basin areas to the north.
In August 2001 a resident of New River contacted the Arizona Department of Health Services
(ADHS) Office of Environmental Health to request information on the health risks of arsenic in
drinking water. The resident collected two well water samples and submitted them to a private
laboratory for arsenic analysis. The analyses detected arsenic at 560 and 600 µg/L. To confirm
these very high arsenic results, ADHS staff sampled the well for arsenic and submitted the
samples for analysis by the ADHS State Laboratory. Arsenic was detected at 340 µg/L. Staff
advised the well owner of potential health effects from this exposure and advised discontinuance
of domestic well water use.
ADHS determined that the health risk posed by arsenic levels in this range and the exclusive
reliance of area residents on private wells warranted further investigation. Initial conversations
with the well owner and New River/ Desert Hills Community Association members revealed
concerns about potential health effects from arsenic exposure. Also, many residents had not had
their private wells tested. Consequently ADHS initiated a private well sampling program to
determine if arsenic contamination of private wells was a widespread problem in the New River
area.
The objective of this public health consultation is to evaluate the potential health effects from
exposure to arsenic in private drinking water wells in the New River, Arizona area.
Methods
On October 7, 2001, in a presentation to the New River / Desert Hills Community Association by
ADHS staff, community members were informed of the detection of elevated arsenic levels in a
local well. They were also offered free arsenic testing of their drinking water wells. Nearly all
attendees requested that their wells be sampled. ADHS provided to the attendees fliers describing
the sampling program, and asked that they distribute the fliers throughout the community.
Between October and December 2001 ADHS sampled a total of 21 private wells in the New
River area. A map of the well locations is included in the Appendix. Samples were submitted to
the ADHS State Laboratory for arsenic analysis, as well as for analyses for antimony, barium,
beryllium, cadmium, chromium, selenium, thallium, and nickel. The additional metals were
selected due to their common occurrence in ore deposits in mineralized areas.
ADHS selected a chemical for further toxicological evaluation if that chemical was detected in
excess of the ATSDR chronic exposure comparison value for children. Comparison values are

1

screening values used to determine whether further investigation of a contaminant is necessary—
concentrations of chemicals less than the comparison values are unlikely to cause health effects.
Results
Arsenic was the only chemical detected in any well in excess of the ATSDR chronic exposure
comparison value for children. Of the 21 wells sampled, 16 contained arsenic at levels exceeding
the comparison value. The following table summarizes the analytical results.
Table 1. Private Well Sampling Results
Chemical

Frequency
of
Detection

Range
(µg/L)

ATSDR
Child
Comparison
Value (µg/L)

Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Selenium
Thallium
Nickel

0/21
16/21
0/21
0/21
0/21
3/21
0/21
0/21
0/21

ND-580
ND-98
-

15*
3
700
10
2
100
50
0.5
200

Frequency of
Detection
Above
Comparison
Value
0/21
16/21
0/21
0/21
0/21
0/21
0/21
0/21
0/21

Contaminant
of Concern?

No
Yes
No
No
No
No
No
No
No

*USEPA Region 9 Preliminary Remediation Goal. No ATSDR Comparison Value Available

Discussion
Exposure Quantification
To quantify exposures, ADHS made several assumptions regarding dose intake: Adults residing
in the area are assumed to drink 2 liters of water per day for 30 years from their private wells.
Children are assumed to drink 1 liter of water per day from the well throughout childhood,
defined as 0-6 years of age.
Also, adults and children are assumed to ingest 0.6 ml of water daily from brushing their teeth
twice a day (Barnhart et al.1974). Bathing was not considered to contribute to exposure, as only
a negligible amount of arsenic is absorbed through dermal contact with contaminated water
(ATSDR 2000). The dose calculations assume an adult body weight of 70 kilograms (kg) and a
child bodyweight of 15 kg. The exposure variables and equations used to determine exposure can
be found in the Appendix.
Exposure Analysis
To evaluate the health effects of exposure to contaminants in specific environmental media,
including water, soil, and air, ATSDR has developed a Minimal Risk Level (MRL) comparison

2

value for common chemical contaminants. The MRL is an estimate of daily human exposure to a
contaminant below which non-cancerous, adverse health effects are unlikely to occur. MRLs are
developed for acute (less than 14 days), intermediate (14 to 365 days), and chronic (greater than
365 days) exposure.
That health guidance values such as MRLs represent a level above which toxicity is likely to
occur is a common misconception. The MRL is neither a threshold for toxicity nor a level
beyond which toxicity is likely to occur. MRLs are established solely as screening tools to
determine whether further evaluation of the contaminant is necessary. Toxicological information
used to derive MRLs and to evaluate the likelihood of health effects resulting from exposures to
contaminants are contained in documents known as toxicological profiles, published by ATSDR.
These chemical-specific profiles provide information on health effects, environmental transport,
human exposure, and regulatory status.
When exposure estimates exceed MRLs additional evaluation is necessary to determine whether
a health hazard exists. Literature sources are reviewed to determine what exposure doses have
been documented to actually cause a health problem. The No Observed Adverse Effect Level
(NOAEL) is the highest exposure dose at which no effect was observed on the animal or human
population in a study. The Lowest Observed Effect Level (LOAEL) for a chemical is the lowest
exposure dose at which a measurable adverse health effect is observed in a human or animal
study population. Whenever possible, when evaluating possible health effects from exposure to
the contaminant, NOAELs and LOAELs from studies in humans are reviewed. If, however, no
human studies exist, studies on laboratory animals are reviewed. Also, the health assessor might
include safety factors to address human differences when evaluating whether health effects might
be possible. The Appendix contains a discussion of potential health effects from chronic oral
arsenic exposure.
Private Well Health Hazard Analysis
ADHS calculated the estimated daily exposure doses of arsenic for each well in which the
arsenic concentration exceeded the ATSDR chronic childhood comparison value, as displayed in
Table 2. Sixteen of 21 wells sampled contained arsenic levels exceeding the comparison value.
Arsenic was not detected in the other five wells. To evaluate the potential for adverse health
effects, estimated arsenic exposure doses were compared to the chronic MRL, NOAEL, and
LOAEL. Both cancer and non-cancer health effects were evaluated. Fourteen of the 16 wells
contained arsenic at a concentration that might cause an adverse health effect in children. Five of
the 16 wells contained arsenic at a concentration that might cause an adverse health effect in
adults. No geographic pattern was evident in the locations of the wells with elevated arsenic
levels.

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Table 2. Well Arsenic Dose Estimates and Comparison Values
Well
Number

Child’s Estimated
Daily Dose
(mg/kg/day)

Child
Dose
Exceeds
MRL?

Child
Dose
Exceeds
NOAEL?

Child
Dose
Exceeds
LOAEL?

1
2
3
4
5
6
7
8
11
13
15
16
17
18
19
20

0.0013
0.0015
0.0020
0.0021
0.0019
0.0073
0.0035
0.0016
0.0008
0.0011
0.0227
0.0387
0.0013
0.0011
0.0007
0.0041

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
No
Yes

No
No
No
No
No
Yes
No
No
No
No
Yes
Yes
No
No
No
No

Arsenic Health Effect Thresholds
The NOAEL range for chronic exposure to arsenic ranges from 0.0004 to 0.0009 mg/kg/day.
Exposures in this range would not be expected to result in adverse health effects in exposed
persons. Health effects from exposure to arsenic have been observed at doses as low as 0.005
mg/kg/day. The health effects observed at the LOAEL include reports of fatigue, headache,
dizziness and numbness (ATSDR 2000). Health effects at slightly higher doses than the
LOAEL (0.0015 mg/kg/day) include scaling of the skin and slight changes in skin pigmentation
(ATSDR 2000). More significant health effects such as significant changes in skin pigmentation
(hyperkeratosis), increased blood pressure, kidney problems, and lung problems have been
observed at doses in the 0.05 mg/kg/day range.

Well 1
The estimated arsenic exposure dose for children of 0.0013 mg/kg/day exceeds the MRL (0.0003
mg/kg/day) and the NOAEL range (0.0004 to 0.0009 mg/kg/day). The dose is only 4 times lower
than the LOAEL (0.005 mg/kg/day), . This suggestings that exposure to arsenic from this well
might cause subtle health effects in children, such as fatigue, numbness or changes in skin
pigmentation.

4

The estimated adult exposure dose of 0.0005 is within the NOAEL range, and is 10 times lower
than the LOAEL, suggesting that arsenic in this well should not pose even a non-cancer health
hazard to adults.
The arsenic concentration in Well 1 was 19 µg/L; lower than the current drinking water standard
of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic at 19
µg/L would pose a cancer risk of less than 1 in 3,000.
As a precaution, ADHS recommends that due to elevated arsenic levels, this well not be used for
drinking water, cooking, or preparing such items as infant formula. Other residential uses of the
water such as bathing and brushing teeth pose no apparent health hazard.

Well 2
The estimated child exposure dose of 0.0015 mg/kg/day exceeds the NOAEL range and is only 3
times lower than the LOAEL, suggesting that exposure to arsenic from this well might cause
subtle health effects in children, such as as fatigue, numbness or changes in skin pigmentation.
The estimated exposure dose for adults of 0.0006 mg/kg/day is within the NOAEL range and is
almost 10 times lower than the LOAEL, suggesting that arsenic in this well should not pose a
non-cancer health hazard to adults.
The arsenic concentration in Well 2 was 23 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 23 µg/L in drinking water would pose a cancer risk of less than 1 in 3,000.
As a precaution, ADHS recommends that this well not be used for drinking water, cooking, or
preparing items such as infant formula. Other residential uses of the water such as bathing and
brushing teeth pose no apparent health hazard.
Well 3
The estimated child exposure dose of 0.002 mg/kg/day is close to the LOAEL of 0.005
mg/kg/day, suggesting that exposure to arsenic from this well might cause subtle health effects in
children, such as fatigue, numbness, or changes in skin pigmentation. The estimated adult
exposure dose of 0.0008 mg/kg/day is within the NOAEL range and is more than 6 times lower
than the LOAEL, suggesting that to adults, arsenic in this well should not even pose a non-cancer
health hazard.
The arsenic concentration in Well 3 was 30 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 30 µg/L in drinking water would pose a cancer risk of less than 1 in 2,000.
As a precaution, ADHS recommends that this well not be used for drinking water, cooking, or
preparing such items as infant formula. Other residential uses of the water such as bathing and
brushing teeth pose no apparent health hazard.

5

Well 4
The estimated child exposure dose of 0.0021 mg/kg /day is close to the LOAEL of 0.005
mg/kg/day, suggesting that arsenic in this well might cause subtle health effects in children, such
as fatigue, numbness, or changes in skin pigmentation. The estimated adult exposure dose of
0.0009 mg/kg/day is equivalent to the highest NOAEL. and is 6 times lower than the LOAEL.
This suggests that arsenic in this well should not pose a non-cancer health hazard to adults.
The arsenic concentration in Well 4 was 32 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 32 µg/L in drinking water would pose a cancer risk of less than 1 in 2,000.
As a precaution, ADHS recommends that this well not be used for drinking water, cooking, or
preparing items such as infant formula. Other residential uses of the water such as bathing and
brushing teeth pose no apparent health hazard.

Well 5
The estimated child exposure dose of 0.0019 mg/kg/day is close to the LOAEL of 0.005
mg/kg/day. This suggests that exposure to arsenic from this well might cause subtle health
effects in children, such as fatigue, numbness, or changes in skin pigmentation. The estimated
adult exposure dose of 0.0008 mg/kg/day is within the NOAEL range and is more than 6 times
lower than the LOAEL, suggesting that to adults, arsenic in this well should not even pose a noncancer health hazard.
The arsenic concentration in Well 5 was 29 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 29 µg/L in drinking water would pose a cancer risk of less than 1 in 2,000.
As a precaution, ADHS recommends that this well not be used for drinking water, cooking, or
preparing such items as infant formula. Other residential uses of the water such as bathing and
brushing teeth pose no apparent health hazard.
Well 6
The estimated child exposure dose of 0.0073 mg/kg/day exceeds the LOAEL, suggesting that
arsenic in the well might cause subtle health effects in children, such as fatigue, numbness, or
changes in skin texture and pigmentation. An adult’s estimated exposure dose of 0.0031 is close
to the LOAEL, suggesting that arsenic in the well might also cause health effects in adults, such
as fatigue, numbness, or changes in skin pigmentation and texture.
The arsenic concentration in Well 6 was 110 µg/L—higher than the current drinking water
standard of 50 µg/L and the 2006 standard of 10 µg/L. Lifetime exposure to arsenic at 110 µg/L
in drinking water presents a cancer risk of approximately 1 in 500.
ADHS recommends that this well not be used for drinking water, cooking, or preparing items
such as infant formula. Other residential uses of the water such as bathing and brushing teeth
pose no apparent health hazard.

6

Well 7
The estimated child exposure dose of 0.0035 is close to the LOAEL, suggesting that arsenic in
the well might cause subtle health effects in children, such as fatigue, numbness, or changes in
skin pigmentation. The adult estimated exposure dose of 0.0015 exceeds the NOAEL range and
is only 3 times lower than the LOAEL, suggesting that arsenic in the well might also cause
health effects in adults, such as changes in skin pigmentation and texture.
Arsenic was detected in Well 7 at 53 µg/L—higher than the current drinking water standard of
50 µg/L and the 2006 standard of 10 µg/L. Lifetime exposure to arsenic at 53 µg/L in drinking
water presents a cancer risk of approximately 1 in 1,000.
ADHS recommends that this well not be used for drinking water, cooking, or preparing items
such as infant formula. Other residential uses of the water such as bathing and brushing teeth
pose no apparent health hazard.

Well 8
The estimated child exposure dose of 0.0016 exceeds the NOAEL range, and is only 3 times
lower than the LOAEL, suggesting that arsenic in the well might cause subtle health effects in
children, such as fatigue, numbness, or changes in skin pigmentation. The adult estimated
exposure dose of 0.0007 is in the NOAEL range, and is almost 10 times lower than the LOAEL,
suggesting that arsenic in the well should not pose a non-cancer health hazard to adults.
The arsenic concentration in Well 8 was 24 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 24 µg/L in drinking water would pose a cancer risk of less than 1 in 2,000.
As a precaution, ADHS recommends that this well not be used for drinking water, cooking, or
preparing such items as infant formula. Other residential uses of the water, such as bathing and
brushing teeth, pose no apparent health hazard.
Well 9
No arsenic was detected in this well, so use of the water poses no apparent health hazard.
Well 10
No arsenic was detected in this well, so use of the water poses no apparent health hazard.
Well 11
The estimated child exposure dose of 0.0008 is within the NOAEL range, and is more than 6
times lower than the LOAEL, suggesting that arsenic in the well should not pose a non-cancer
health hazard to children. The adult estimated exposure dose of 0.0003 is lower than the NOAEL
and is 17 times lower than the LOAEL, suggesting that arsenic in the well does not present a
non-cancer health hazard for adults.

7

The arsenic concentration in Well 11 was 12 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 12 µg/L in drinking water would pose a cancer risk of less than 1 in 5,000.
This well poses no apparent health hazard.
Well 12
No arsenic was detected in this well, so use of the water poses no apparent health hazard.
Well 13
The estimated child exposure dose of 0.0011 mg/kg/day exceeds the NOAEL range and is
slightly only 4 times lower than the LOAEL. This suggests that arsenic in this well might cause
subtle health effects in children, such as fatigue, numbness, or changes in skin pigmentation.
The estimated adult dose of 0.0005 is within the NOAEL range, and is 10 times lower than the
LOAEL. This suggests that arsenic in this well should not pose a non-cancer health hazard to
adults.
The arsenic concentration in Well 13 was 17 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 17 µg/L would pose a cancer risk of less than 1 in 3,000.
As a precaution, ADHS recommends that due to elevated arsenic levels this well not be used for
drinking water, cooking, or preparing items such as infant formula. Other residential uses of the
water such as bathing and brushing teeth pose no apparent health hazard.
Well 14
No arsenic was detected in this well, so use of the water poses no apparent health hazard.
Well 15
The estimated child exposure dose of 0.0227 is over 4 times higher than the LOAEL, indicating
that arsenic in this well might cause health effects in children, such as diarrhea, nausea, changes
in skin pigmentation, and growth of corns or warts on palms, soles of feet, and torso. The
estimated adult exposure dose of 0.0097 exceeds the LOAEL, indicating that arsenic in the well
might cause health effects in adults, such as diarrhea, nausea, changes in skin pigmentation, and
growth of corns or warts on palms, soles of feet, and torso.
The arsenic concentration in Well 15 was 340 µg/L—much higher than the current drinking
water standard of 50 µg/L and the 2006 standard of 10 µg/L. Lifetime exposure to arsenic in
drinking water at 340 µg/L would pose a cancer risk of approximately 1 in 200.
If any family members are experiencing symptoms that they believe might be related to arsenic
exposure, they should see their health care provider.
ADHS recommends that due to elevated arsenic levels this well not be used for drinking water,
cooking, or preparing any food items, including infant formula. Other residential uses of the
water, such as bathing and brushing teeth pose no apparent health hazard.

8

Well 16
The estimated child exposure dose of 0.0387 mg/kg/day is nearly 8 times higher than the
LOAEL, indicating that arsenic in this well might cause health effects in children, such as
diarrhea, nausea, changes in skin pigmentation, and growth of corns or warts on palms, soles of
feet, and torso. The adult estimated exposure dose of 0.0166 is more than 3 times higher than the
LOAEL, indicating that arsenic in this well might cause health effects in adults, such as diarrhea,
nausea, changes in skin pigmentation, and growth of corns or warts on palms, soles of feet, and
torso.
The arsenic concentration in Well 16 was 580 µg/L— much higher than the current drinking
water standard of 50 µg/L and the 2006 standard of 10 µg/L. Lifetime exposure to arsenic in
drinking water at 580 µg/L would pose a cancer risk of approximately 1 in 100.
If any family members are experiencing symptoms that they believe might be related to arsenic
exposure, they should see their health care provider.

ADHS recommends that due to elevated arsenic levels this well not be used for drinking water,
cooking, or preparing such items as infant formula. Other residential uses of the water, such as
bathing and brushing teeth pose no apparent health hazard.
Well 17
The estimated child exposure dose of 0.0013 mg/kg/day exceeds the NOAEL range and is only 4
times lower than the LOAEL, suggesting that arsenic in this well might cause subtle health
effects in children, such as fatigue, numbness, or changes in skin pigmentation. The estimated
adult exposure dose of 0.0006 mg/kg/day is within the NOAEL range and is almost 10 times
lower than the LOAEL, suggesting that that arsenic in this well should not pose a non-cancer
health hazard to adults.
The arsenic concentration in Well 17 was 20 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 20 µg/L would pose a cancer risk of less than 1 in 3,000.
As a precaution, ADHS recommends that due to elevated arsenic levels this well not be used for
drinking water, cooking, or preparing such items as infant formula. Other residential uses of the
water, such as bathing and brushing teeth, pose no apparent health hazard.
Well 18
The estimated child exposure dose of 0.0011 mg/kg/day exceeds the NOAEL range and is only 4
times lower than the LOAEL, suggesting that arsenic in this well water might cause subtle health
effects in children, such as fatigue, numbness, or changes in skin pigmentation. The estimated
adult exposure dose of 0.0005 mg/kg/day is within the NOAEL range and is 10 times lower than
the LOAEL, suggesting that arsenic in the well should not pose a non-cancer health hazard to
adults.

9

The arsenic concentration in Well 18 was 16 µg/L—lower than the current drinking water
standard of 50 µg/L, but higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic
at 16 µg/L would pose a cancer risk of less than 1 in 3,000.
As a precaution, ADHS recommends that due to elevated arsenic levels this well not be used for
drinking water, cooking, or preparing such items as infant formula. Other residential uses of the
water, such as bathing and brushing teeth, pose no apparent health hazard.
Well 19
The estimated child exposure dose of 0.0007 mg/kg/day is within the NOAEL range and is
almost 10 times lower than the LOAEL, suggesting that this well should not pose a non-cancer
health hazard to children. The estimated adult arsenic dose of 0.0003 is below the NOAEL, and
is 16 times lower than the LOAEL, indicating that arsenic in this well should not pose a noncancer health threat to adults.
Arsenic was detected in Well 19 at 11 µg/L—lower than the current drinking water standard of
50 µg/L, but just higher than the 2006 standard of 10 µg/L. Lifetime exposure to arsenic at 11
µg/L in drinking water presents a cancer risk of less than 1 in 5,000.
This well poses no apparent health hazard.
Well 20
The estimated child exposure dose of 0.0041 mg/kg/day is close to the LOAEL, suggesting that
arsenic in this well might cause subtle health effects in children, such as fatigue, numbness, or
changes in skin pigmentation. The estimated adult exposure of 0.0017 mg/kg/day exceeds the
NOAEL range and is only 3 times lower than the LOAEL, suggesting that arsenic in the well
might also cause subtle health effects in adults, such as fatigue, numbness, or changes in skin
pigmentation.
Arsenic was detected in Well 20 at 62 µg/L—higher than the current drinking water standard of
50 µg/L and the 2006 standard of 10 µg/L. Lifetime exposure to arsenic at 62 µg/L in drinking
water presents a cancer risk of less than 1 in 1,000.
ADHS recommends that this well not be used for drinking water, cooking, or preparing
beverages, including infant formula. Other residential uses of the water, such as bathing and
brushing teeth, present no apparent health hazard.
Well 21
No arsenic was detected in this well, so use of the water poses no apparent health hazard.
Child Health Initiative
All exposure dose estimates were calculated assuming childhood exposure, thus incorporating
exposure assumptions that reflect a child’s greater intake of water relative to body weight. All
conclusions and recommendations about using water from these wells were based on this
sensitive population.

10

Conclusions
•

Seven of the 21 wells (9-12, 14, 19, and 21) pose no apparent health hazard.

? Fourteen of the wells (1-8, 13, 15-18 and 20) pose a health hazard for children if the
water is used for drinking; arsenic is present in the water at levels that might cause subtle
adverse health effects in children, such as fatigue, numbness, or changes in skin
pigmentation..
•

Five of the wells (6, 7, 15, 16, and 20) pose a health hazard for children and adults if
the water is used for drinking; arsenic is present in the water at levels that might cause
adverse health effects in adults such as fatigue, numbness, or changes in skin
pigmentation.

•

Two of the wells (15 and 16) have very high concentrations of arsenic in the water.
These wells pose a health hazard for children and adults if the water is used for drinking.
Water from these wells might cause more health effects, such as diarrhea, nausea,
changes in skin pigmentation, and growth of corns or warts on palms, soles of feet, and
torso.

•

All of the wells tested pose no apparent health hazard if the water is used only for
bathing, washing dishes, tooth brushing and general sanitary purposes.

•

Other private wells in the area were not tested. Some of these wells could contain
contaminants at levels that might cause adverse health effects.

Recommendations
•

Residents of homes whose drinking water is supplied from wells 1-8, 13, 15-18, and 20
should either install a treatment system that effectively removes arsenic or find an
alternative source of drinking water.

•

All residents in the New River area who use well water for drinking or beverage
preparation should test their well water for arsenic.
Public Health Action Plan

•

ADHS has previously notified well owners whose wells were determined to be a health
hazard in this study.

•

ADHS will offer to present the findings of this investigation at a 2002 New River/ Desert
Hills Community Association meeting.

11

•

ADHS will mail a letter to all registered private well owners in the New River/ Desert
Hills area, including investigation findings and a recommendation to have their well
water tested for arsenic. The mailing will be completed by September 2002.

•
If any community member would like their health care provider to have additional
information on arsenic exposure and health effects, ADHS will provide that information.

12

References
[ATSDR] Agency for Toxic Substances and Disease Registry. 2000. Toxicological profile for
arsenic. Atlanta: US Department of Health and Human Services.
Barnhart WE et al. 1974. Dentifrice usage and ingestion among four age groups. J Dent Res
53:1317-25.
[CEPA] California Environmental Protection Agency. 1996. Abandoned mines and mining
waste. Sacramento, California: California Environmental Protection Agency.

13

Preparers of Report
Arizona Department of Health Services, Office of Environmental Health
Amy Welch, Environmental Health Specialist
Will Humble, Chief, Office of Environmental Health, Principal Investigator
ATSDR Technical Project Officer
Gail Godfrey
Division of Health Assessment and Consultation
Superfund Site Assessment Branch
State Programs Section
ATSDR Regional Representative
William Nelson
Office of Regional Operations, Region IX
Office of the Assistant Administrator

14

Appendix
1. Map showing locations of sampled wells.
2. Health effects from chronic arsenic ingestion.
3. Arsenic exposure dose equations.

15

Health Effects from Chronic Arsenic Ingestion
One of the most common effects of both acute and long-term arsenic ingestion is a pattern of
skin changes, including changes in skin pigmentation (hyperpigmentation, interspersed with
small areas of hypopigmentation of the face, neck, and back), generalized hyperkeratosis, or
thickening of the skin, and formation of hyperkeratotic warts on the palms and soles. These
effects are most often reported at chronic dose levels ranging from about 0.01 to 0.1 mg/kg/day.
Human studies document gastrointestinal irritation from chronic oral exposure to arsenic at dose
levels of about 0.01 mg/kg/day and above. Symptoms include nausea, diarrhea, and vomiting.
Damage to the liver and elevated levels of hepatic enzymes are reported at dose levels of 0.01 to
0.01 mg/kg/day. Hematological effects, including anemia and, have been documented at chronic
oral exposures of 0.05 mg/kg/day and above. Neurological effects are reported at chronic oral
doses of 0.03-0.01 mg/kg/day, including peripheral neuropathy and numbness in hands and feet,
possibly developing into a painful “pins and needles” sensation.
Cardiovascular effects include cardiac arrhythmia and myocardial depolarization. A serious
vascular condition called Blackfoot disease is endemic in an area of Taiwan where residents are
exposed to arsenic in drinking water from about 0.014-0.065 mg/kg/day. Studies in Chile report
indicate that consumption of drinking water doses of 0.02-0.06 mg/kg/day increases in the
incidence of Raynaud’s disease and cyanosis of the fingers and toes (ATSDR 2000).
Arsenic has been classified as a human carcinogen by the U.S. Environmental Protection Agency
(USEPA), the National Toxicology Program (NTP), and the International Agency for Research
on Cancer (IARC). Reports indicate that arsenic in drinking water increases the risk of skin,
liver, bladder, kidney, lung, and prostate cancer. Studies suggest that cancer effects might occur
following long-term exposure (ATSDR 2000).

16

Exposure Dose Equations
ADHS used the ATSDR exposure assessment documents to calculate an exposure dose for
persons living in the New River area. The doses were calculated using the following equations:
Ingestion of chemicals in water:
CDI= CW x IR x EF x ED
BW x AT
CDI: chronic daily intake (mg/kg/day)
CW: concentration in water (mg/L)
IR: intake rate (L/day)
EF: exposure frequency (days/yr)
ED: exposure duration (yrs)
BW: body weight (kg)
AT: Averaging time (days)
-----------------------------------------------------------------Variable Assumptions
Adults
Children
IR (ingestion, water):
EF:
ED:
BW:
AT:

2
350
30
70
10950

1
350
6
15
2190

Water Intake Rate for Tooth brushing
Fluoride concentration:
Estimated fluoride ingestion:
Estimated water intake:

1 mg/ ml water*
0.3 mg/ brushing*
0.3 ml/ brushing x 2 brushings = 0.6ml/day

* Barnhart et al. 1974

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